1. Field of the Invention
The present invention relates generally to function synthesizers, and particularly to a CMOS (complementary metal oxide semiconductor) programmable non-linear function synthesizer that can realize arbitrary nonlinear functions using programmable transistor squaring units without dedicated current multipliers.
2. Description of the Related Art
U.S. Pat. No. 7,952,395, issued to the present first-named inventor, Muhammad Taher Abuelma'atti et al, on May 31, 2011, discloses a universal CMOS current-mode analog function synthesizer. The proposed circuit of U.S. Pat. No. 7,952,395 is based upon the fact that numerous nonlinear functions can be approximated, to a high degree of accuracy, using a few terms of their Taylor series expansion.
Moreover, U.S. Pat. No. 7,952,395 teaches how to provide current multipliers having reasonable bandwidth and low complexity (thus, low power consumption), while eliminating the need to trim out the feed-through terms (offset currents) and while eliminating the necessity to adjust the scale factor (the multiplier gain). Yet there remains the problem of how to program such a device for arbitrary functions, not just the thirty-two functions shown in the patent.
Thus, a CMOS programmable non-linear function synthesizer solving the aforementioned problems is desired.